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From: felipe.balbi on 17 May 2010 06:10
From: Felipe Balbi <felipe.balbi(a)nokia.com>

Few architectures, like OMAP, allow you to set
a debouncing time for the gpio before generating
the IRQ. Teach gpiolib about that.

Signed-off-by: Felipe Balbi <felipe.balbi(a)nokia.com>
---
drivers/gpio/gpiolib.c | 43 +++++++++++++++++++++++++++++++++++++++++++
include/asm-generic/gpio.h | 5 +++++
include/linux/gpio.h | 5 +++++
3 files changed, 53 insertions(+), 0 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index eb0c3fe..cd85fd1 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1447,6 +1447,49 @@ fail:
}
EXPORT_SYMBOL_GPL(gpio_direction_output);

+/**
+ * gpio_set_debounce - sets @debounce time for a @gpio
+ * @gpio: the gpio to set debounce time
+ * @debounce: debounce time is microseconds
+ */
+int gpio_set_debounce(unsigned gpio, unsigned debounce)
+{
+ unsigned long flags;
+ struct gpio_chip *chip;
+ struct gpio_desc *desc = &gpio_desc[gpio];
+ int status = -EINVAL;
+
+ spin_lock_irqsave(&gpio_lock, flags);
+
+ if (!gpio_is_valid(gpio))
+ goto fail;
+ chip = desc->chip;
+ if (!chip || !chip->set || !chip->set_debounce)
+ goto fail;
+ gpio -= chip->base;
+ if (gpio >= chip->ngpio)
+ goto fail;
+ status = gpio_ensure_requested(desc, gpio);
+ if (status < 0)
+ goto fail;
+
+ /* now we know the gpio is valid and chip won't vanish */
+
+ spin_unlock_irqrestore(&gpio_lock, flags);
+
+ might_sleep_if(extra_checks && chip->can_sleep);
+
+ return chip->set_debounce(chip, gpio, debounce);
+
+fail:
+ spin_unlock_irqrestore(&gpio_lock, flags);
+ if (status)
+ pr_debug("%s: gpio-%d status %d\n",
+ __func__, gpio, status);
+
+ return status;
+}
+EXPORT_SYMBOL_GPL(gpio_set_debounce);

/* I/O calls are only valid after configuration completed; the relevant
* "is this a valid GPIO" error checks should already have been done.
diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h
index 979c6a5..ce3eb87 100644
--- a/include/asm-generic/gpio.h
+++ b/include/asm-generic/gpio.h
@@ -88,6 +88,9 @@ struct gpio_chip {
unsigned offset);
int (*direction_output)(struct gpio_chip *chip,
unsigned offset, int value);
+ int (*set_debounce)(struct gpio_chip *chip,
+ unsigned offset, unsigned debounce);
+
void (*set)(struct gpio_chip *chip,
unsigned offset, int value);

@@ -121,6 +124,8 @@ extern void gpio_free(unsigned gpio);
extern int gpio_direction_input(unsigned gpio);
extern int gpio_direction_output(unsigned gpio, int value);

+extern int gpio_set_debounce(unsigned gpio, unsigned debounce);
+
extern int gpio_get_value_cansleep(unsigned gpio);
extern void gpio_set_value_cansleep(unsigned gpio, int value);

diff --git a/include/linux/gpio.h b/include/linux/gpio.h
index 4e949a5..03f616b 100644
--- a/include/linux/gpio.h
+++ b/include/linux/gpio.h
@@ -51,6 +51,11 @@ static inline int gpio_direction_output(unsigned gpio, int value)
return -ENOSYS;
}

+static inline int gpio_set_debounce(unsigned gpio, unsigned debounce)
+{
+ return -ENOSYS;
+}
+
static inline int gpio_get_value(unsigned gpio)
{
/* GPIO can never have been requested or set as {in,out}put */
--
1.7.1

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Prev: leds-lp3944: properly handle lp3944_configure fail in lp3944_probe
Next: [PATCH 0/6] teach gpiolib about gpio debouncing